Tuesday, 21 September 2010

Chlorine Dioxide - Disinfection of Bottling Plants

Chlorine dioxide is not new for disinfection.  It has been used for many years in water treatment and in the brewing industry for disinfecting pipelines by CIP.  Application in the bottled water industry has been overlooked.  There could be several reasons for that, for example cost were high at one time and special equipment was required to generate the chlorine dioxide gas safely.

Things have changed and it is now possible to generate chlorine dioxide for application as a CIP disinfectant very easily and often manually.  Chlorine dioxide is a gas, which will dissolve in water to produce a strongly oxidising disinfectant.  The gas can be very unstable and will break down quickly unless stabilised by careful pH control.  It has considerable advantages over chlorine-based disinfectants and does not form halomethanes or ketones if in contact with residual organic material.  If formed, these materials impart a very strong medicinal taste to water.

Chlorine dioxide is formed by the reaction of sodium chlorite solution with an acid.  In the bottled water industry, citric acid is the preferred acid.  The gas is generated and dissolves in water.  The amount of water added determines the final concentration of the product.  Chlorine dioxide is particularly good at destroying biofilm in pipework and is to be preferred over peracetic acid for this task.

The basic components required to form chlorine dioxide are available from Food Hygiene Technologies Ltd along with easy-to-follow use instructions.

Monday, 2 August 2010

Titrations to determine bottle wash detergent or peracetic acid concentration can be complicated and some involve at least three reagents. However, new drop-test kits and test strips are available that make the whole process much easier.

Using ozonation as a final terminal disinfection in bottle washing can be effective, but only if used at the correct concentration. 0.4mg/l is not sufficient and concentrations of 0.8mg/l are required for effective disinfection. 0.4mg/l will disinfect the rinse water, but not the bottle surfaces.

Only certain treatments are allowed for natural mineral water and spring water. Natural mineral water ideally should receive no treatment at all. Make sure that your labelling complies with the regulations.

Reducing greening of bottles is possible by correct choice of bottle wash detergent. The best option is to use a detergent containing a disinfectant component and wash at temperatures above 60°C. Alternatively, pre-washing equipment and chemicals are available to handle this problem.

Is your Colilert® test working? Some conditions can give false positives.

Hydrogen peroxide disinfectants are ideal for use in the bottling plant and for cooler servicing because there are no taint problems and no residuals.

ATP meters have become smaller, more robust and distinctly more affordable. Measuring points include taps, reservoirs and drip trays.